It is better to be silent, and be thought a fool, than to speak and remove all doubt.

attributed to someone named Silvan Engel.
None of the sites gave any further information about or any more quotes from Silvan Engel.
In the past month, the same attribution has popped up on many other pages:

saying that Lincoln was quoting Silvan Engel. But still not a word about
who this Engel was!
I don't find a single hit on "Silvan" and "Engel" in any library catalog I've tried--including the
Library of Congress.
Was there really such a person, or is this all just a demonstration of the way a completely fictional attribution worms its way into public consciousness?